Ink jet printer apparatus and method of printing

Abstract

An ink jet printer prints dot matrix characters by removing unwanted drops from a sequence of uniformly spaced drops in an ink jet stream and subjecting the remaining print drops to a vertical raster deflection in timed relation with relative horizontal motion of the jet stream and a record medium. Selected print drops are individually deflected fractional amounts in either the horizontal or vertical direction prior to the vertical raster deflection to cause the selected print drops to be deposited at positions intermediate the coordinate intercepts of a rectilinear matrix pattern to cause dot matrix characters to be printed with arcuate line segments and various angles corresponding with conventional character shapes.

I claim: 
     
       1. A method of printing characters on a record medium with individual drops of ink comprising projecting a sequence of uniformly-spaced ink drops in a first direction toward said record medium while effecting relative motion between the record medium and said stream in a second direction orthogonal to said first direction,   said drops in said sequence being at least equal in number to the number of coordinate intercepts of a predetermined rectilinear matrix pattern, and   forming data markings on said record medium with said drops in accordance with a predetermined data pattern including   selectively removing unwanted drops from said sequence to cause blanks at predetermined coordinate intercepts of said matrix pattern,   deflecting the remaining drops from said sequence in a third direction orthogonally to said first and second directions so as to cause said remaining drops to be directed to impact predetermined intercept locations of said matrix pattern, and   altering the deflection of certain of said remaining drops in either said second or third direction for causing said certain drops to be directed to locations intermediate coordinate intercepts of said matrix pattern.   
     
     
       2. Apparatus for printing data on a record medium with individual ink drops comprising means for projecting a sequence of uniformly-spaced ink drops in a first direction toward said record medium,   said drops in said sequence being at least equal in number to the number of coordinate intercepts of a predetermined rectilinear matrix pattern,   means for effecting relative motion between said record medium and said sequence of drops in a second direction orthogonal to said first direction,   means for selectively removing unwanted drops from said sequence to cause blanks at predetermined coordinate intercepts of said matrix pattern,   means for deflecting the remaining drops of said sequence in a third direction orthogonally to said first and second directions so as to cause said remaining drops to be directed to impact predetermined intercept locations of said matrix pattern, and   means for altering the deflection of certain of said remaining drops in either said second or third directions for causing said certain drops to be directed to locations intermediate the coordinate intercepts of said matrix pattern.   
     
     
       3. Apparatus for printing data on a record medium with individual ink drops comprising means for projecting a sequence of uniformly-spaced ink drops in a straight line trajectory perpendicular to said record medium,   said drops in said sequence being at least equal in number to the number of coordinate intercepts of a predetermined rectilinear matrix pattern;   means for effecting relative motion of said record medium and said projecting means in a horizontal direction;   means for selectively removing unwanted drops from said sequence to cause blanks at predetermined coordinate intercepts of said matrix pattern including drop catcher means proximate said record medium and offset from the trajectory of said ink drops, and   means for deflecting unwanted drops in a second trajectory towards said drop catcher means; means for deflecting the remaining drops of said sequence vertically to cause said remaining drops to be directed to impact predetermined intercept locations of said matrix pattern, and     means for further deflecting certain of said remaining drops either horizontally or vertically causing said certain drops to be redirected to locations intermediate the coordinate intercepts of said matrix pattern.   
     
     
       4. Apparatus for printing data on a record medium in accordance with claim 3 in which said ink drops are formed of field controllable fluid,   said means for selectively removing unwanted drops comprises field transducer means for directing unwanted drops towards a catcher means,   said means for deflecting the remaining drops comprises a field transducer operable to generate a vertical scanning field, and   said means for altering the deflection of certain of said remaining drops comprises transducer means for generating a deflection field either vertically or horizontally predetermined fractional amounts for causing said certain drops to be redirected to locations intermediate the coordinate intercepts of said matrix pattern.   
     
     
       5. Apparatus for printing data on a record medium in accordance with claim 4 in which said ink drops are magnetic ink drops, and   said transducers for selectively removing unwanted drops, deflecting the remaining drops, and for altering the deflection of certain of the remaining drops all comprise magnetic field transducers located along the trajectory of said magnetic ink drops.   
     
     
       6. Apparatus for printing data on a record medium in accordance with claim 5 in which said magnetic transducer means for altering the deflection of said remaining magnetic ink drops comprises a first magnetic transducer for deflecting certain of said remaining drops a fractional amount in a vertical direction, and   a second magnetic transducer spaced from said first magnetic transducer for deflecting said magnetic ink drops a fractional amount horizontally relative to the trajectory of said ink drops, and means for selectively energizing said first and second magnetic transducers for deflecting certain of the remaining drops in either said vertical or horizontal direction for causing said certain drops to be directed to locations horizontally or vertically intermediate the coordinate intercepts of said matrix pattern.     
     
     
       7. Apparatus for printing data on a record medium in accordance with claim 6 in which said means for selectively removing unwanted drops and for altering the deflecting of certain remaining drops in a horizontal direction comprises a single transducer element located adjacent the trajectory of said ink drops, and   means for operating said transducer element selectively at different levels to direct said unwanted drops toward said drop catcher or to a horizontal location intermediate the coordinate intercepts of said matrix pattern.